Maybe he'd like to get to know you better, but he's shy and unsure what to say in an actual message. Or, he might be the kind of guy who winks at a lot of woman and can't be bothered sending a message. If this is the case, it doesn't mean much.
The law of conservation of mass (from Lavoisier) states that mass can be neither created nor destroyed (but it may change its form into something that is not desired, such as heat with an engine) or that in a chemical reaction, the total mass of the reacting substances is equal to the total mass of products formed.
Law of conservation of energy. The law of conservation of energy is one of the basic laws of physics and therefore governs the microscopic motion of individual atoms in a chemical reaction. In a closed system, i.e., a system that isolated from its surroundings, the total energy of the system is conserved.